The invention relates to pumps, and more particularly to a bi-directional, single stage or multi-stage pump, which has a number of unique advantages.
The prior art discloses a great variety of pumps. However, traditionally, pumps are designed for a particular use. Each use, traditionally, compels the use of a pump having different flow and head requirements. Many times pumps having more capacity than is required for the use are used simply because pumps having the right requirements are not available.
It is therefore highly desirable to provide a full range of pumps for a variety of uses. This is extremely difficult in manufacturing pumps, it being difficult to design a pump having the variety of flow and head requirements necessary. Pump manufacturers have long sought a unitized pump structure which can be easily assembled and is inexpensive to manufacture and which can be assembled with motors of different sizes as a single stage or a multi-stage pump as required.
In a number of uses, it is further highly desirable to provide pumps that are lubricated by the flow of fluid through the pump and/or to provide a pump-motor combination structure by which the motor is both cooled and lubricated by the flow of fluid through the pump.